Category Archives: Microbiology

Research – Salmonella, Listeria and E. coli: opportunistic bacteria

Posted on June 29, 2020 by | Leave a comment

Oulah

Researchers at the University of Delaware are examining how certain bacteria manage to bypass plant immune defenses.

As the world battles against the coronavirus pandemic (COVID-19), which emerged after the virus moved from animal to human, researchers at the University of Delaware are learning new ways to other pathogens jump from plants to humans

Opportunistic bacteria,  Salmonella ,  Listeria  and  E. coli , for example – often attach themselves to raw vegetables, poultry, beef and other foods to enter a human host, causing millions of illnesses each year food.

But researchers from the University of Delaware,  Harsh Bais  and  Kali Kniel  and their collaborators have now discovered that wild strains of  Salmonella  can bypass a plant’s immune system, penetrating lettuce leaves by opening tiny pores. of the plant called stomata.
The plant has no symptoms of this invasion and once inside the plant, the pathogens cannot simply be washed out.

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Salmonella, Uncategorized

Australia – Salmonella illnesses linked to backyard chickens in Australia

Posted on June 29, 2020 by | Leave a comment

Food Safety News

 

Authorities in an Australian state are investigating an outbreak of Salmonella linked to contact with or consumption of eggs from backyard chickens.

The Victorian Department of Health and Human Services is looking into nine cases of gastroenteritis caused by Salmonella Enteritidis. People became sick between late April and the end of May.

Professor Brett Sutton, chief health officer in Victoria, said investigations so far have not identified a common source, but most cases had contact with, or consumed eggs from backyard chickens.

The Department of Health and Human Services is following up all notified cases of Salmonella Enteritidis and working with Agriculture Victoria and the chief veterinary officer to manage the infection in these chickens.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbiology, Salmonella, Salmonella in Chicken, Uncategorized

Research – Evaluation of weakly acidic electrolyzed water and modified atmosphere packaging on the shelf life and quality of farmed puffer fish (Takifugu obscurus ) during cold storage

Posted on June 28, 2020 by | Leave a comment

Wiley Online

The combined effect of weakly acidic electrolyzed water (WAEW) and modified atmosphere packaging (MAP) treatments on the quality of puffer fish (Takifugu obscurus ) during cold storage was studied on aspects of microbiological activity, texture, total volatile basic nitrogen (TVB‐N), trimethylamine (TMA), free amino acids (FAAs), thiobarbituric acid reactive substance (TBARS), ATP‐related compounds and K value, volatile organic compounds (VOCs), and organoleptic properties. As a result, significantly (p  < .05) higher inhibitory effects on total viable counts (TVC), H2S‐producing bacteria (including Shewanella putrefaciens ), Pseudomonas spp., and lactic acid bacteria (LAB) were observed in WAEW‐treated puffer fish packaged in 60%CO2/5%O2/35%N2 atmosphere than that in air package and vacuum package with/without WAEW‐treated samples. In addition, chemical results showed that WAEW together with MAP treatments were highly efficient in maintaining lower TVB‐N, TMA, and TBARS values in refrigerated puffer fish. Moreover, the presence of WAEW combined with MAP treatments showed positive effects on retarding the relative content of fishy flavor compounds, such as 1‐octen‐3‐ol, 1‐penten‐3‐ol, hexanal, heptanal, nonanal, decanal, (E )‐2‐octenal, and 2,3‐butanedione. As a whole, the combined effect of WAEW and MAP on refrigerated puffer fish is advisable to maintain better quality and extend the shelf life.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Pseudomonas, Pseudomonas aeruginosa, Pseudomonas fluorescens, Research, Shewanella, Technology, Uncategorized

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Posted on June 27, 2020 by | Leave a comment

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s (p  < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss (p  < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

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Posted in Coliforms, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, lactic acid bacteria, microbial contamination, Microbiology, mold, Moulds, Research, Uncategorized, Yeasts

Research – Antibacterial activities of Camellia sinensis plant extracts against uropathogenic E. coli in vitro and in vivo

Posted on June 27, 2020 by | Leave a comment

AJ

This study evaluated the in vitro and in vivo antibacterial activities of methanol and ethyl acetate extracts of Camellia sinensis (Green tea) against Escherichia coli implicated in urinary tract infections. Antibacterial activities of these plant extracts were tested against 10 multi-drug resistant E. coli isolates obtained from clinical specimens of UTI patients. Forty-five (45) Wister albino rats were used for this study and exactly 0.1 ml of standardized (0.5 McFarland’s) E. coli suspension was each inoculated into the 45 rats through intra-urethral route and observed after 48 h. This was followed by oral administration of different concentrations of methanol and ethyl acetate extracts of C. sinensis, and ciprofloxacin antibiotic for 14 days. Phytochemical screening of extracts showed the presence of bioactive components. Results revealed that methanol extract was better than ethyl acetate extract of C. sinensis in the treatment of UTI caused by E. coli. Body weight, white blood cell count, and erythrocyte sedimentation rate level returned to normal values after treatment with methanol extract of C. sinensis at 200 mg/kg body weight when compared to ethyl acetate extract of C. sinensis. This study has shown that C. sinensis possess bioactive ingredients with antimicrobial activities. Information from this study adds to the current information on the potential health benefits of green tea. Thus, further studies on other plant products should be explored so as to understand their potential health benefits and as alternative therapeutics in the treatment of bacterial infections.

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Posted in E.coli, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Research, Uncategorized

Research – Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli on Vegetable Seeds Contaminated by Direct Contact with Artificially Inoculated Soil during Germination

Posted on June 26, 2020 by | Leave a comment

JFP

ABSTRACT

Contaminated vegetable seeds have been identified as a potential source of foodborne bacterial pathogens. This study was undertaken to observe the behavior of Salmonella and enterohemorrhagic Escherichia coli (EHEC) on vegetable seeds, contaminated by direct contact with artificially inoculated soil, during germination. Sterile sandy soil inoculated with lyophilized cells of four individual strains of Salmonella or EHEC (three O157:H7 strains and one O104:H4 strain) was mixed with sanitized seeds (2 g) of alfalfa, fenugreek, lettuce, and tomato at 20°C for 1 h. The contaminated seeds were germinated on 1% water agar at 25°C for 9 days in the dark. Populations of Salmonella and EHEC on various tissues (seed coat, root, cotyledon, and stem, etc.) of sprouts and seedlings were determined every other day over the germination period. Overall, 70.4 and 72.4% of collected tissue samples (n = 544) tested positive for Salmonella and EHEC, respectively. In general, the mean populations of Salmonella and EHEC on sprout and seedling tissues increased with the prolongation of germination time. Seed coats had the highest bacterial counts (4.00 to 4.06 log CFU/0.01 g), followed by the root (3.36 to 3.38 log CFU/0.01 g), cotyledon (3.13 to 3.38 log CFU/0.01 g), and stem tissues (2.67 to 2.84 log CFU/0.01 g). On average, tissue sections of fenugreek sprouts and lettuce seedlings had significantly higher (P < 0.05) numbers of Salmonella and EHEC cells than that of alfalfa sprouts and tomato seedlings. Data suggest that the growth and dissemination of Salmonella and EHEC cells on alfalfa, fenugreek, lettuce, and tomato sprout and seedling tissues are influenced by the type of vegetable seeds and sprout and seedling tissues involved. The study provides useful information on the fate of two important foodborne bacterial pathogens on selected vegetable seeds, contaminated by direct contact with inoculated soil, during the germination process.

HIGHLIGHTS
  • Vegetable seeds were contaminated via contact with pathogen-bearing sandy soil.
  • Pathogens on contaminated seeds were recovered from tissues of sprouts and seedlings.
  • Tomato and alfalfa tissues had lower pathogen counts than fenugreek and lettuce tissues.
  • Seed coats had higher pathogen counts than the root and cotyledon tissues.
  • Stem tissues had lower Salmonella/EHEC counts compared with all other tissues.

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Posted in Campylobacter, E.coli O157, E.coli O157:H7, EHEC, Food Micro Blog, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbiology, Salmonella, Uncategorized

Research -Exposure Assessment of Multiple Mycotoxins in Black and White Sesame Seeds Consumed in Thailand

Posted on June 26, 2020 by | Leave a comment

JFP

ABSTRACT

This study was conducted to determine the occurrence of 16 well-recognized and emerging mycotoxins in black and white sesame seed samples sold in Thailand and to evaluate possible health risks to consumers. Samples were extracted and cleaned with a modified QuEChERS procedure. Multiple mycotoxins in sesame seed samples were analyzed with a validated liquid chromatography–tandem mass spectrometry method. The risk of mycotoxin exposure via dietary intake of sesame seeds was evaluated based on the hazard quotient, margin of exposure (MOE), and quantitative liver cancer risk established by European Food Safety Authority, the Food and Agriculture Organization of the United Nations, and the World Health Organization. Of the 200 samples, 21.5% were contaminated with mycotoxins, 19.5% were contaminated with a single mycotoxin, and 2% were contaminated with multiple mycotoxins. Although 9% of total samples were contaminated with aflatoxins (AFs), only one black sesame seed sample and one white sesame seed sample were above the regulatory limits for the European Union (2 μg/kg). The MOE values derived from consumption of black and white sesame seeds were generally <10,000, especially in the group consuming the most. The number of liver cancer cases over a lifetime associated with AFB1 exposure based on the upper bound values for the group consuming high level of black and white sesame seeds (97.5 percentile) was estimated at more than 1 case per one million persons. Therefore, a potential risk to consumer health exists through the consumption of black and white sesame seeds and subsequent exposure to AFB1. However, further evaluation with larger sample sizes is necessary for more accurate calculations. Continuous monitoring of mycotoxin contamination in sesame seeds with risk assessments is recommended.

HIGHLIGHTS
  • Beauvericin, sterigmatocystin, and aflatoxins are frequently found in sesame seed samples.
  • Mycotoxin contamination in most samples was below European Union stipulations.
  • A potential risk to consumer health exists through consumption of sesame seeds.
  • Evaluation of mycotoxin contamination is important to maintain consumer safety.

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Posted in Aflatoxin, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Toxin, Fusarium Toxin, microbial contamination, Microbiology, mold, Mould Toxin, Moulds, Mycotoxin, Research, Uncategorized

RASFF Alert – Enterobacteriaceae -Frozen Dog Raw Feed

Posted on June 26, 2020 by | Leave a comment

RASFF-Logo

RASFF – too high count of Enterobacteriaceae (43000 CFU/g) in frozen dog raw feed from the United Kingdom in Slovenia

 

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Posted in Animal Feed, Enterobacteriaceae, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbiology, RASFF, Uncategorized

RASFF Alert – Salmonella – Processed Animal Proteins

Posted on June 26, 2020 by | Leave a comment

RASFF-Logo

RASFF – Salmonella (in 2 out of 5 samples /25g) in processed animal proteins from Spain in Italy

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Posted in Animal Feed, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbiology, RASFF, Salmonella, Uncategorized

Research – Survival of toxigenic Escherichia coli on chamomile, peppermint, green, black, ginger, and cinnamon teas during storage and brewing

Posted on June 25, 2020 by | Leave a comment

Wiley Online

In this study, the persistence of toxigenic Escherichia coli (E. coli ) on dried chamomile, peppermint, ginger, cinnamon, black and green teas stored under 4, 10, and 25°C was determined. The E. coli survival rate in ginger and cinnamon teas decreased below 0 on Day 5. In the other tested teas, E. coli survivability showed a downward trend over time, but never dropped to 0. Chamomile tea retained the greatest population of viable E. coli . Meanwhile, die‐off of E. coli was higher at 25°C compared to lower temperatures. Additionally, fate of E. coli during brewing at 60, 70 and 80°C was evaluated. The E. coli population was reduced to below 2 Log colony forming units (CFU)/g after 1 min at 80°C, At the same time, the E. coli survival at 60°C was higher than that at 70°C in all tested teas. The data indicated that if E. coli survives after storage of prepared teas, it may also survive and grow after the brewing process, especially if performed using temperatures <80°C. Finally, we analyzed the correlations between temperature, time, tea varieties and E. coli survival, and successfully constructed a random forest regression model. The results of this study can be used to predict changes in E. coli during storage and fate during the brewing process. Results will form the basis of undertaking a risk assessment.

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiology, Research, Uncategorized